THE EFFECT OF GLASS-IONOMER CEMENT ON CARIOUS DENTIN - AN IN-VIVO STUDY

The effect of a glass-ionomer cement sealant on carious dentine was investigated clinically and bacteriologically. The study group consisted of 24 molar teeth, with small clinical visible occlusal dentine lesions. in 13 children (aged 7-18 years). Twenty of these molars were filled and sealed with a glass-ionomer cement (Fuji Ionomer Type III(R)) and 4 with a resin sealant (Delton(R)). From each molar, two dentine samples were collected aseptically with a time interval of 7 months. The first sample was taken after opening the lesion just beneath the dentino-enamel junction before application of the filling material (sample A), and the second beneath the removed filling material (sample B) 7 months later. Before collecting sample B the sealant was clinically evaluated and impressions were prepared in order to (re)evaluate the sealants later by scanning electron microscopy (SEM). After taking the second sample, the remaining fissures were opened to a standard depth, the caries which was still present was removed, and a composite resin restoration was applied. In all teeth, more glass-ionomer cement material was found by SEM compared to the clinical evaluation. In both the glass-ionomer- and the resin sealant-treated group, the median value of the total number of microorganisms (CFU) on blood agar was 100 times smaller in the B sample. Microorganisms were found in 90% of the B samples in the group treated with glass-ionomer cement; hard dentine was also found in 45% of the B samples from this group, No significant differences were found between the groups in terms of dentine colour, hardness, or numbers and types of microorganisms (Fisher's exact test, p>0.05). There appears to be some evidence of an effect by glass-ionomer cement on the consistency of remaining carious dentine. However, it would be premature to conclude from the results obtained in this study that complete removal of carious dentine need not be carried out when using glass-ionomer cement.